st: Attaching Out of Sample data to the present Dataset in Memory

Basically, I would like to do forecasting based on my estimated model.
My data sample is given over 1958-2000. I need to do prediction out of
this sample, say, 2001-2043. I have already defined some scenarios about
the annual average growth rate of each right hand-side variables in my
model and based on that I have simulated out-of -sample dataset over
2001 -2043 for all right hand-side variables in the model .

Actually, I want to attach these simulated data set to the dataset which
is already in Stata`s memory over 1958-2000. I am not sure how can I
perform this job on Stata. Is there any command to perform this job on
Stata? I use version 8.2 of Stata software. Can anybody help me out on
this matter?